[PATCH 6.9 157/374] media: ti: j721e-csi2rx: Fix races while restarting DMA

Greg Kroah-Hartman
2024-06-06T14:09:38Z

From: Jai Luthra <j-luthra@ti.com>

[ Upstream commit ad79c9ecea5baa7b4f19677e4b1c881ed89b0c3b ]

After the frame is submitted to DMA, it may happen that the submitted
list is not updated soon enough, and the DMA callback is triggered
before that.

This can lead to kernel crashes, so move everything in a single
lock/unlock section to prevent such races.

Fixes: b4a3d877dc92 ("media: ti: Add CSI2RX support for J721E")
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
index 6da83d0cffaae..22442fce76078 100644
--- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
+++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
@@ -786,15 +786,14 @@ static void ti_csi2rx_buffer_queue(struct vb2_buffer *vb)
dev_warn(csi->dev,
"Failed to drain DMA. Next frame might be bogus\n");

+ spin_lock_irqsave(&dma->lock, flags);
ret = ti_csi2rx_start_dma(csi, buf);
if (ret) {
- dev_err(csi->dev, "Failed to start DMA: %d\n", ret);
- spin_lock_irqsave(&dma->lock, flags);
vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
dma->state = TI_CSI2RX_DMA_IDLE;
spin_unlock_irqrestore(&dma->lock, flags);
+ dev_err(csi->dev, "Failed to start DMA: %d\n", ret);
} else {
- spin_lock_irqsave(&dma->lock, flags);
list_add_tail(&buf->list, &dma->submitted);
spin_unlock_irqrestore(&dma->lock, flags);
}
--
2.43.0